The present invention relates to a driving circuit for a matrix liquid crystal display device in which a switching element is provided to each of an array of picture elements disposed over the display area.
A matrix liquid crystal display device, in which a group of line electrodes is arranged perpendicular to another group of line electrodes, can be operated with a low voltage and consuming little power. It is therefore widely used for character/picture display means of pocketable electronic devices. In this type of display device, however, the picture contrast deteriorates with gradual decrease of the duty factor because of crosstalk, when multiplex operation is conducted. Accordingly, it is difficult to obtain a picture of satisfactory contrast for a large capacity display. In contrast, if a switching transistor is added to each of the picture elements disposed over the display area of a matrix liquid crystal display device, the switching transistors suppress crosstalk so that, even with multiplex operation with a small duty factor, the display device provides a picture of the same clear contrast as with static operation. The matrix liquid crystal display device with switching transistors is, therefore, suitable as a large capacity display device.
The conventional driving circuit for a liquid crystal display device consumes a large amount of power for half tone display. This large power requirement makes it difficult to manufacture small liquid display devices. In addition, clock frequency increases with the volume of information to be displayed, thus multiplying the power consumption by the driving circuit.